1. Field of the Invention
The present invention pertains to an apparatus for measuring the turbidity of a liquid, including measuring the presence of oil or other contaminants in water, wherein a windowed chamber is defined for measuring the change in the intensity of a light beam, and the chamber is arranged to prevent fouling of the windows by isolating the contaminated or turbid fluid stream from contact with the windows by clear fluid wash streams.
2. Background
My U.S Pat. No. 4,809,543, assigned to the assignee of the present invention, describes an apparatus for measuring the turbidity of a fluid stream, in particular for use in determining the concentration of oil and water. This apparatus has an arrangement wherein the turbid flowstream is directed into the interior of a vessel defining a turbidity chamber wherein a light source is beamed through the chamber by way of opposed windows and onto a photosensitive element such as a photoresister.
Although the apparatus provides for a superior method for determining the concentration of oil in water, or the turbidity of a fluid flowstream, certain fluids include impurities which are so adherent that accumulations occur on the windows, despite the turbulence caused by the arrangement of liquid jets which face the windows. Efforts to provide suitable window materials which do not become coated with liquid contaminants have heretofore been unsuccessful.